The invention relates to an ignition spark emitter for fuel operated heating devices.
Dependent upon the type of burner installed, it has been customary to use an ignition spark emitter, in fuel operated heating devices, which has two ignition electrodes whose free ends are positioned relative to the burner nozzle outlet in such a way that an emission of ignition sparks, controlled by a transformer, will ignite a mixture of fuel and air produced in the area of the nozzle outlet. To this end, the ignition electrodes are connected via electrical lines to a power supply unit that is remote from the burner nozzle assembly and which also contains a transformer for the controlled production of ignition sparks. In such a situation, the ignition electrodes must be attached and correspondingly aligned, and the attachment as well as the alignment of the ignition electrodes is time-consuming and costly. Cable connection of the ignition electrodes with the electrical power unit not only results in transmission losses, but also may entail disturbances in the high frequency range.
It is the objective of the invention to develop an ignition spark emitter for fuel operated heating devices which may be contained in the heating device in a space-saving manner, while also providing a reliable operation without transmission losses or high frequency disturbances.
In accordance with a preferred embodiment of the invention, the ignition spark emitter for fuel operated heating devices is characterized in that the ignition electrodes can be secured to a housing which contains the transformer and the power supply units, and further in that a plug connector is provided for the electrical connection of the ignition spark emitter housing, which connector serves as a mount for the entire ignition spark emitter.
In the ignition spark emitter in accordance with the invention, by securement of the ignition electrodes at the housing, alignment of the electrode spacing can be eliminated, since the housing simultaneously serves as the mounting for the ignition electrodes. Due to the fact that the housing also contains the transformer and a power supply unit, line connections, like ignition cables, which previously have been necessary, can be eliminated, so that a loss-free energy supply is achieved, in which high frequency disturbances are suppressed. A substantial simplification in mounting of the inventive ignition spark emitter is further realized in that the housing not only serves as a mount for the ignition electrodes, but has a plug connection for the electrical connection, preferably a multipolar plug-in unit by which the ignition spark emitter housing, together with the ignition electrodes, is secured at a predetermined point in the heating device. In order to prevent the disengagement of the ignition spark emitter housing plug connection, the ignition spark emitter housing can also be secured, for instance, by means of screws, after the plug connection has been established.
The plug connection of the housing of the ignition spark emitter contains a minimum of one control input, via which it can be addressed, such that it can be switched on and off, and its pulse frequency as well as its input duration can be controlled. Preferably, a control unit of the heating device determines the control input volumes, without, however, a requiring a relay. As a consequence, an energy free control is realized.
In accordance with an advantageous further embodiment, the ignition spark emitter is designed so that an ignition electrode, in connection with a ground circuit, is utilized for ionization flame monitoring. Accordingly, two functions are integrated into the ignition spark emitter, namely that of the actual ignition device and that of flame monitoring. Therefore, separate components for flame monitoring can be eliminated, whereby the assembly of such heating device is simplified. The ground circuit can be established by having the ignition spark sender housing conductively connected with a combustion tube of the heating device, preferably by way of a connecting flange.
Appropriately, in this dual function embodiment, an analyzer for the ionization flame monitoring device is provided, whose output is connected with a pole of the plug connector so that, via the plug connection, dependent upon the determined result of the analyzer, a signal is retransmitted to the control device. If, subsequent to the ignition process, a flame has formed in the combustion chamber of the heating device, a signal is sent to the control unit, via the output of the analyzer, that indicates this flame. If conversely, no flame has formed after the ignition process, another signal will cause, via the control unit, the ignition process to be repeated.
In order to obtain a construction of the ignition spark emitter which is space-saving and compact, the transformer of the emitter contained in the ignition spark housing is switched in a time multiplex process, so that it can be utilized for ignition spark delivery as well as ionization flame monitoring.
If, furthermore, the ignition electrodes are detachably secured to the housing, for instance, by provision of a plug connector, the electrodes can be easily coordinated to the size of the heating device, and the heating capacity delivered by the heating device. Thus, without altering the basic structural form of the ignition spark emitter, the ignition electrodes can be quickly and easily exchanged, facilitating also a more economical inventory of the components, since a number of different electrodes may be attached to the same basic emitter unit.
In accordance with the invention, the ignition spark emitter housing, with the ignition electrodes and the elements contained in the housing, is preferably arranged as close as possible to the burner nozzle assembly. Such an arrangement is realized due to the fact that the ignition spark emitter housing may be made as small and compact as possible.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.